docs: Add submission note for OpenCode projects

Added a note about submitting projects to the list.

packages/web/src/content/docs/ecosystem.mdx

@@ -5,7 +5,11 @@ description: Projects and integrations built with OpenCode.
 
 A collection of community projects built on OpenCode.
 
-For more, check out [awesome-opencode](https://github.com/awesome-opencode/awesome-opencode).
+:::note
+Want to add your OpenCode related project to this list? Submit a PR.
+:::
+
+You can also check out [awesome-opencode](https://github.com/awesome-opencode/awesome-opencode).
 
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